Some radars detect and track space objects, such as space debris and satellites, primarily in Low Earth Orbit (LEO). Low Earth Orbit typically refers to distances from the Earth's surface to 2,000 kilometers away, but that is just an example with no limitation to that definition intended. Most satellites and the International Space Station operate in LEO, which makes tracking of debris and other objects even more important.
To improve detectability of the objects and measure them with high range and Doppler resolution, the desired operation would be integrated measurements of the space object over long periods of time. High Doppler resolution means that the radar can detect objects that travel relatively close together. In this context, long periods of time may run several hundreds of milliseconds or longer. These long periods of time conflict with the transmission limitations required to resolve the distance to the target, which may range from a few hundred to a few thousand kilometers.
Many radars have functional constraints, including pulse duration, duty cycle limitations, minimum transmission and/or reception periods, etc. Achieving the long periods of time for measurement integration for accurate tracking becomes difficult, if not impossible for some radars.